Methylchloroform, a commonly used degreasing solvent may be prepared by liquid phase hydrochlorination of vinylidene chloride in the presence of a Friedel-Krafts catalyst, e.g., ferric chloride, as described for example in U.S. Pat. No. 2,209,000. Regardless of the mode of the preparation methylchloroform is typically recovered from the crude reaction mixture by distillation, however during distillation, methylchloroform tends to decompose to vinylidene chloride and hydrogen chloride which vinylidene chloride tends to polymerize often resulting in equipment fouling.
It is desirable therefore, to provide means for inhibiting decomposition of methylchloroform undergoing purification distillation as well as to provide means for inhibiting polymerization of methylchloroform decomposition product, i.e., vinylidene chloride.